1. Field of the Invention
The present invention relates generally to printing images on packaging material, and specifically to generating and printing digital images onto a web of packaging material for plastic pouches and laminated material packages such as parallelepiped containers and cartons
2. Description of the Related Art
Creators of packages and containers have provided their products with images since before history was recorded. However, from pre-Columbian pottery to polyethylene pouches, the process of creating and transferring imagery to containers has been labor-intensive, time-consuming, and wasteful of materials. This remains true despite the many changes that have taken place in the printing industry over the past decade.
The computer has been responsible for much of this revolution, particularly in the prepress industry. The influence of the computer was felt first in art creation, color separation, and proofing. As is evident from the ever-expanding arena of desktop publishing, many of these changes are still in progress, driven by the rapid advances made in the world of electronic communications.
Along with these changes, a peculiar imbalance has developed in the industry. While prepress operations in most firms were influenced dramatically by the advent of the computer, the pressroom has remained essentially undisturbed for years. In many printing plants, it has become commonplace to find the most modern technologies used to create artwork and even to process films and plates, while the package material printing process still employs plates or cylinders, press make-ready, printing and finishing operations that differed little from those in use for decades. Thus, packagers create and prepare artwork on computers, often in a matter of hours, only to end up using the same printing equipment and techniques known to their grandparents. These processes often take weeks to complete, consuming vast amounts of labor and energy while generating mountains of waste.
Concurrent with, but largely independent of, this revolution in artwork preparation, market pressures in the computer industry have resulted in the rapid development of new printing devices. Among these new devices are digital, non-impact printers using laser jet or bubble jet technologies, which have become commonplace in even the smallest offices. Despite their widespread acceptance in a variety of environments, these technologies have yet to be applied in an effective way in the production of printed substrates, such as packaging materials.
In the packaging industry, the most commonly used printing techniques are gravure and offset. In a typical gravure printing process, it is not unusual for five to nine weeks to pass between the time of creation of original artwork until packaging material delivery to the customer. The gravure process can generally be described as follows. Once the packaging producer receives the artwork, it must be checked. Next, separations and bromide proofs are made and checked, then forwarded to the customer for approval. Once the bromide proofs are approved, the producer generates a lithographic, or "litho", proof, which is again checked and sent to the customer. After the customer approves the litho proof, the package producer makes cylinders, then runs and checks cylinder proofs, and sends them to the customer for approval. If the cylinder proofs are acceptable, the press is prepared and set up. With the press set up, packaging material can be run, and subsequently delivered to the customer.
The offset process, while typically requiring somewhat less time than gravure, is similarly complex and time consuming. Once the packaging producer receives the artwork, it must be checked. Next, separations and match proofs are made and checked, then forwarded to the customer for approval. Once the match proofs are approved, the producer generates a litho proof, which is again checked and sent to the customer. After the customer approves the litho proof, the package producer exposes and develops plates, which are then mounted on the press. Next, the press blankets are cleaned, the press is set up, and the inks are balanced. The press is then ready for packaging material to be run, and subsequently delivered to the customer. The entire offset process often consumes from two to seven weeks.
Thus, it can be seen that, while electronic prepress has developed and become accepted as the norm in the production of packaging material, the development of suitable printing systems has lagged behind. It would be advantageous to provide a package material printing system using electronic printing techniques to print directly on to the desired substrate, thus reducing the number of steps from creation of a design to production of material, while reducing prepress work and eliminating vast amounts of waste. Such a system would increase productivity due to drastically reduced order-change and set-up time.
Current technology has allowed for the printing of small, one color (black) text on packages. However, this current technology is not a substitute for the full color printing produce through gravure and offset printing. What is needed is a printing system that may compete with, or even replace the gravure and offset printing techniques.